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From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-mm@kvack.org, linux-arch@vger.kernel.org,
	linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Andy Lutomirski <luto@kernel.org>,
	Balbir Singh <bsingharora@gmail.com>,
	Borislav Petkov <bp@alien8.de>,
	Cyrill Gorcunov <gorcunov@gmail.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Eugene Syromiatnikov <esyr@redhat.com>,
	Florian Weimer <fweimer@redhat.com>,
	"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Kees Cook <keescook@chromium.org>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Nadav Amit <nadav.amit@gmail.com>,
	Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
	Peter Zijlstra <peterz@infradead.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
	Dave Martin <Dave.Martin@arm.com>,
	Weijiang Yang <weijiang.yang@intel.com>,
	Pengfei Xu <pengfei.xu@intel.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>,
	Mark Brown <broonie@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>
Subject: [PATCH v14 23/26] ELF: Introduce arch_setup_elf_property()
Date: Mon, 12 Oct 2020 08:38:47 -0700
Message-ID: <20201012153850.26996-24-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20201012153850.26996-1-yu-cheng.yu@intel.com>

An ELF file's .note.gnu.property indicates arch features supported by the
file.  These features are extracted by arch_parse_elf_property() and stored
in 'arch_elf_state'.  Introduce arch_setup_elf_property() for enabling such
features.  The first use-case of this function is shadow stack.

ARM64 is the other arch that has ARCH_USER_GNU_PROPERTY and arch_parse_elf_
property().  Add arch_setup_elf_property() for it.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
---
 arch/arm64/include/asm/elf.h |  5 +++++
 arch/x86/Kconfig             |  2 ++
 arch/x86/include/asm/elf.h   | 13 +++++++++++++
 arch/x86/kernel/process_64.c | 32 ++++++++++++++++++++++++++++++++
 fs/binfmt_elf.c              |  4 ++++
 include/linux/elf.h          |  6 ++++++
 6 files changed, 62 insertions(+)

diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h
index 8d1c8dcb87fd..d37bc7915935 100644
--- a/arch/arm64/include/asm/elf.h
+++ b/arch/arm64/include/asm/elf.h
@@ -281,6 +281,11 @@ static inline int arch_parse_elf_property(u32 type, const void *data,
 	return 0;
 }
 
+static inline int arch_setup_elf_property(struct arch_elf_state *arch)
+{
+	return 0;
+}
+
 static inline int arch_elf_pt_proc(void *ehdr, void *phdr,
 				   struct file *f, bool is_interp,
 				   struct arch_elf_state *state)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 7578327226e3..4b28a0ce4594 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1950,6 +1950,8 @@ config X86_SHADOW_STACK_USER
 	select X86_CET
 	select ARCH_MAYBE_MKWRITE
 	select ARCH_HAS_SHADOW_STACK
+	select ARCH_USE_GNU_PROPERTY
+	select ARCH_BINFMT_ELF_STATE
 	help
 	  Shadow Stacks provides protection against program stack
 	  corruption.  It's a hardware feature.  This only matters
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index b9a5d488f1a5..0e1be2a13359 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -385,6 +385,19 @@ extern int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
 					      int uses_interp);
 #define compat_arch_setup_additional_pages compat_arch_setup_additional_pages
 
+#ifdef CONFIG_ARCH_BINFMT_ELF_STATE
+struct arch_elf_state {
+	unsigned int gnu_property;
+};
+
+#define INIT_ARCH_ELF_STATE {	\
+	.gnu_property = 0,	\
+}
+
+#define arch_elf_pt_proc(ehdr, phdr, elf, interp, state) (0)
+#define arch_check_elf(ehdr, interp, interp_ehdr, state) (0)
+#endif
+
 /* Do not change the values. See get_align_mask() */
 enum align_flags {
 	ALIGN_VA_32	= BIT(0),
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 9afefe325acb..8725e67bcd44 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -837,3 +837,35 @@ unsigned long KSTK_ESP(struct task_struct *task)
 {
 	return task_pt_regs(task)->sp;
 }
+
+#ifdef CONFIG_ARCH_USE_GNU_PROPERTY
+int arch_parse_elf_property(u32 type, const void *data, size_t datasz,
+			     bool compat, struct arch_elf_state *state)
+{
+	if (type != GNU_PROPERTY_X86_FEATURE_1_AND)
+		return 0;
+
+	if (datasz != sizeof(unsigned int))
+		return -ENOEXEC;
+
+	state->gnu_property = *(unsigned int *)data;
+	return 0;
+}
+
+int arch_setup_elf_property(struct arch_elf_state *state)
+{
+	int r = 0;
+
+	if (!IS_ENABLED(CONFIG_X86_CET))
+		return r;
+
+	memset(&current->thread.cet, 0, sizeof(struct cet_status));
+
+	if (static_cpu_has(X86_FEATURE_SHSTK)) {
+		if (state->gnu_property & GNU_PROPERTY_X86_FEATURE_1_SHSTK)
+			r = cet_setup_shstk();
+	}
+
+	return r;
+}
+#endif
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 13d053982dd7..2b4cfc256895 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1217,6 +1217,10 @@ static int load_elf_binary(struct linux_binprm *bprm)
 
 	set_binfmt(&elf_format);
 
+	retval = arch_setup_elf_property(&arch_state);
+	if (retval < 0)
+		goto out;
+
 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
 	retval = arch_setup_additional_pages(bprm, !!interpreter);
 	if (retval < 0)
diff --git a/include/linux/elf.h b/include/linux/elf.h
index 5d5b0321da0b..4827695ca415 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -82,9 +82,15 @@ static inline int arch_parse_elf_property(u32 type, const void *data,
 {
 	return 0;
 }
+
+static inline int arch_setup_elf_property(struct arch_elf_state *arch)
+{
+	return 0;
+}
 #else
 extern int arch_parse_elf_property(u32 type, const void *data, size_t datasz,
 				   bool compat, struct arch_elf_state *arch);
+extern int arch_setup_elf_property(struct arch_elf_state *arch);
 #endif
 
 #ifdef CONFIG_ARCH_HAVE_ELF_PROT
-- 
2.21.0


  parent reply index

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-12 15:38 [PATCH v14 00/26] Control-flow Enforcement: Shadow Stack Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 01/26] Documentation/x86: Add CET description Yu-cheng Yu
2020-11-06 17:34   ` Borislav Petkov
2020-11-06 18:16     ` Yu, Yu-cheng
2020-11-06 18:28       ` Borislav Petkov
2020-11-06 18:32         ` Yu, Yu-cheng
2020-10-12 15:38 ` [PATCH v14 02/26] x86/cpufeatures: Add CET CPU feature flags for Control-flow Enforcement Technology (CET) Yu-cheng Yu
2020-11-06 18:49   ` Borislav Petkov
2020-11-06 19:48     ` Yu, Yu-cheng
2020-11-06 20:11       ` Borislav Petkov
2020-11-06 20:14         ` Yu, Yu-cheng
2020-10-12 15:38 ` [PATCH v14 03/26] x86/fpu/xstate: Introduce CET MSR XSAVES supervisor states Yu-cheng Yu
2020-10-12 19:58   ` Cyrill Gorcunov
2020-10-12 20:48     ` Yu, Yu-cheng
2020-10-12 15:38 ` [PATCH v14 04/26] x86/cet: Add control-protection fault handler Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 05/26] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 06/26] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 07/26] x86/mm: Remove _PAGE_DIRTY_HW from kernel RO pages Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 08/26] x86/mm: Introduce _PAGE_COW Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 09/26] drm/i915/gvt: Change _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 10/26] x86/mm: Update pte_modify for _PAGE_COW Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 11/26] x86/mm: Update ptep_set_wrprotect() and pmdp_set_wrprotect() for transition from _PAGE_DIRTY_HW to _PAGE_COW Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 12/26] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 13/26] x86/mm: Shadow Stack page fault error checking Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 14/26] x86/mm: Update maybe_mkwrite() for shadow stack Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 15/26] mm: Fixup places that call pte_mkwrite() directly Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 16/26] mm: Add guard pages around a shadow stack Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 17/26] mm/mmap: Add shadow stack pages to memory accounting Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 18/26] mm: Update can_follow_write_pte() for shadow stack Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 19/26] mm: Re-introduce vm_flags to do_mmap() Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 20/26] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 21/26] x86/cet/shstk: Handle signals for shadow stack Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 22/26] binfmt_elf: Define GNU_PROPERTY_X86_FEATURE_1_AND properties Yu-cheng Yu
2020-10-12 15:38 ` Yu-cheng Yu [this message]
2020-10-12 15:38 ` [PATCH v14 24/26] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 25/26] x86/cet/shstk: Add arch_prctl functions for " Yu-cheng Yu
2020-10-12 15:38 ` [PATCH v14 26/26] mm: Introduce PROT_SHSTK " Yu-cheng Yu

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